Fluctional molecules

Fluctional molecules are defined as molecules that can interconvert rapidly with respect to a reference timescale. The most common timescale is Nuclear Magnetic Resonance (NMR), which is millisecond (10 −3 s). The rate constant of interconversion is given by the Eyring equation $k = {{k_{\rm B} T} \over h}e^{-{{\Delta G^ \pm } \over{RT}}}$ , where k B is Boltzmann constant, T is absolute temperature, h is Planck constant, Δ G ‡ is the Gibbs free energy of activation, and R is gas constant that can be reduced to ln ${k\over T} = 23.76-{{\Delta G^ \pm} \over {RT}}$ . A variety of spectroscopic techniques are often employed to study fluctional processes. © 2011 John Wiley & Sons, Ltd. WIREs Comput Mol Sci 2011 1 943‐951 DOI: 10.1002/wcms.47 This article is categorized under: Theoretical and Physical Chemistry > Reaction Dynamics and Kinetics